1. Field of the Invention
The present invention relates to a process for manufacturing a palladium ternary catalyst and more particularly, to an improved process for manufacturing a palladium ternary catalyst fabricated by reducing a palladium solution containing alumina, adding a mixing solution consisting of barium oxide, etc., adjusting its pH for further reaction, milling the mixture, coating the catalyst materials to a ceramic monolith substrate, and drying and calcinating the composite. As a result, the ternary catalyst of the present invention containing palladium can effectively purify automobile exhaust gas, containing harmful substances together with achieving cost-saving effects, as compared to the conventional ternary catalyst consisting of platinum, rhodium and palladium.
2. Description of the Prior Art
In general, a ternary catalyst refers to a catalyst which serves to remove harmful substances from automobile exhaust gas, such as hydrocarbon compounds, carbon monoxide and nitrogen oxide(NOx), by simultaneous reacting with them. In the past years, the conventional ternary catalyst which have been employed include Pt/Rh, Pd/Rh or Pt/Pd/Rh.
However, the conventional catalyst always contains rhodium(RH) as a necessary catalyst ingredient for reducing nitrogen oxide, from the exhaust gas. However, such an element is expensive and contains a poor heat-resisting property.
With a view toward overcoming the defects in the conventional ternary catalyst, the present inventors have carried out extensive studies have completed the present invention by using palladium only instead of high-priced rhodium in such a manner that palladium is mixed with alumina and through reaction with a base metal oxide, the mixture is milled, coated, dried and calcined.